In recent years shaving razors with various numbers of blades have been proposed in the patent literature and commercialized such as the three-bladed Mach III™ razor and the five bladed Fusion™ razor by The Gillette Company.
Increasing the number of blades on a shaving razor generally tends to increase the shaving efficiency of the razor and provide better distribution of compressive forces on the skin but it can also tend to increase drag forces, reduce maneuverability, and reduce the ability to trim, e.g., sideburns or near the nose. To solve this problem an extra blade can be mounted at the rear of the razor housing for trimming.
Short hairs are typical of hair growth of approximately twenty-four hours. Standard shaving razors cut shorter hairs rather effectively because the short hairs have a tendency to stand straight up. The edge of a trimming blade on the razor is able to cut the short hair at an optimum angle. Longer hairs typically bend over as they grow and lay flat on the skin. The trimming blade will have the tendency to skive or cut the longer hair at a more parallel angle to the skin surface. Some longer hairs may lie flat such that the trimming blade is unable to cut them. The user may have to trim the same area repeatedly to cut hairs that were either uncut or not cut close enough to the skin surface.
It is therefore desirable to provide a shaving razor with a trimming blade having a guard that provides superior long hair cutting performance.